


Demigods x Shadowhunters

by Just_Chillin



Category: Percy Jackson and the Olympians - Rick Riordan, The Mortal Instruments Series - Cassandra Clare
Genre: Camp Half-Blood (Percy Jackson), Crossover, Multi, New York Shadowhunter Institute, Post-Book Series: The Mortal Instruments
Language: English
Status: In-Progress
Published: 2021-02-11
Updated: 2021-03-08
Packaged: 2021-03-17 08:00:47
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 3,023
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29347038
Author URL: https://archiveofourown.org/users/Just_Chillin/pseuds/Just_Chillin
Summary: Will Solace and Nico Di Angelo are on a date when they encounter an odd monster that they have never seen before.The Shadowhunters of The New York Institute realize that there has been strange demonic activity in the streets of Manhatten...
Relationships: Magnus Bane & Alec Lightwood, Nico di Angelo & Will Solace
Comments: 2
Kudos: 9





	1. Chapter 1

**Author's Note:**

> Hewooo
> 
> Trigger Warning: Contains a bit of violence and blood. Mild swearing.  
> This is one of my first stories so constructive criticism is appreciated.

When Will heard that Nico had never been to an amusement park, he yelped and his eyebrows shot up so high they almost disappeared. "You have never been to an amusement park? Never? Ever?", he kept repeating while jumping up and down in Cabin 13 excitedly. Nico rolled his eyes, flopped onto his bed and mumbled, "It's not a big deal, calm down." 

Nico had lost a bet, and now, Will could take him anywhere in the mortal world. Instead of spending his Saturday sulking in his cabin or at least training, he was probably going to spend his day at an amusement park where there definitely was going to be children shrieking. That thought made him sigh so dramatically the back of his throat slightly hurt. 

"Nico, it's not going to be so bad as you think. We can feel like a kid again! Just think of all the rides that we can go on and the carnival, food...", Will's voice trailed off and his eyes turned dreamy. And when he begged, "Please, please, can we go to an amusement park today?", Nico couldn't bring himself to say No, why would I want to listen to screaming children all day? And why would I want to be a kid again-. So he reluctantly said, "Fine, but it better be at least a bit entertaining." 

Even if his day wasn't going to be spent in the comfort of his cabin, the smile that brightened up Will's face and the way his beautiful sky blue eyes shone was worth it. Secretly, Nico knew that as long as he was with Will, his day would be good, if not perfect. 

Will said, "C'mon, you have to actually get up and get ready if we're going to get in before there's a huge crowd" and pulled him to his feet. When their eyes met, Nico couldn't help but blush furiously and turn away to hide his smile. Suddenly, Will cupped his chin and tilted it upwards.

"I love you", he whispered and gently pressed his lips to Nico's. It was brief but sweet and full of affection. It was enough to make Nico turn crimson anyway. 

"Aww, someone is blushing. So cute", Will teased and dodged a pillow aimed at his head. Nico growled, "Shut the fuck up", and flipped him off. Ignoring Will's soft chuckling, he grabbed his sword and shoved it into a sheath attached to his belt. 

"Okay, I'm all ready to...", Nico faltered when he saw the other boy gaping. Will practically shouted, "Are you seriously going to bring a sword to an amusement park?" 

Nico crossed his arms. "Yes. There could be monsters or people that need to die."

"First, that is a slim possibility. Two, no killing anyone today. Three, can you at least take something smaller? You do realize that you are going to have to go on rides with a sharp three-foot sword made of Stygian Iron right?", Will countered. 

"No, I'm bringing my sword or I'm not going. And yes, I know. I've been in more dangerous situations for gods's sake, Will. Can we please go now?" 

In the end, Will gave in but he made Nico promise that he would only take out his sword if they were in immediate danger. Then, they jogged down Half-Blood Hill and climbed into Argus's waiting van. 

"Have fun on your date!", a familiar voice called. Nico saw that it was Kayla and shouted out the window, "It's not a date, Will is just dragging me to an amusement park because apparently sulking in my cabin isn't healthy" but his whole sentence was lost in the wind. Turning around, he saw that Will was smiling and his eyes were twinkling with amusement. 

Will smirked and said, "Not a date, huh? It's just you and me, and you're holding my hand. I think this does count as a date-" 

" I am not...", Nico started to say, but he looked down at their intertwined hands and realized, that he had gotten so used to Will holding his hand that he didn't feel conscious about it anymore. He sighed but didn't pull away like he would have a couple of months ago. 

When they finally got to the amusement park, Argus dropped them off and asked a silent question with his eyes, Do you need a ride back? Nico barely had time to shake his head and thank the driver before an excited Will half dragged him to the entrance. 

Only after they got their tickets and went through the gate did Nico see how truly breathtaking the park was. There were many rollercoasters weaving through each other and a huge Ferris Wheel. As he gazed dreamily at the line of endless food stands and the carnival, Nico indeed felt like a tiny kid again, just as Will had said. 

A melancholy feeling slammed into Nico unexpectantly. The children who screamed with delight and ran around their parents were a reminder of his sister and him as kids. His mind drifted to the way Bianca used to toss her gorgeous long dark brown hair while laughing joyfully. And Nico would shriek and chase her around in the casino...

A sudden warm touch jerked him back to the present and Nico blinked. "Nico, you okay? We can go back to Camp if you want", a kind voice said. Will's. 

Even though his mouth was dry, Nico managed to croak out, "Yeah, I'm okay. I just got...overwhelmed. I don't see these kinds of huge things often. Should we go on the Ferris Wheel?" 

Will's eyes were full of concern, nonetheless, the cheeriness from earlier returned to his voice and he exclaimed, "Sure!" He offered his hand, and Nico gladly took it. 

The two boys went on a clear passenger car and they both were awed by the view at the top. They could see the entire park, the sparkling ocean, and a forest. The people on the ground looked like ants and the carnival looked like a collection of tiny houses.

Nico squinted against the bright midday sun and tried to look past the carnival. He saw the parking lot and...

A dark shadow slowly approaching the park. 

Wishing that it was just a trick of the light, his hallucination, anything but something real, Nico grabbed Will's arm and pointed toward it. When he saw Will's eyes darken, his hopes were squashed. So it was real. And they had to kill it. Typical. 

As he unsheathed his black three-foot sword, Nico shivered despite the warm sun glaring down on his back. He had never felt this way before. Not even in the bronze jar. It was a different kind of dread, fear. Closing his eyes, he tried to block out the negative thoughts. It's going to be fine. I've defeated armies of the worst monsters crawling straight out of Tartarus. So why did he feel so uneasy...

When he opened his eyes again, he couldn't find the shadow anywhere. So...had it been just a trick of the light? Then, he saw something flickering in the parking lot and he knew for sure that whatever that is, it isn't something ordinary. 

Cursing, he realized how fast it was approaching the park. "Won't this damn thing move any faster?", Nico screamed. He got a few weird looks from families nearby but he didn't care. He had to get off soon. 

If the situation wasn't so dire, Will would have surely laughed or at least smiled at Nico's sudden outburst. But his expression only darkened when he too, realized that they didn't have much time and they better get off right now. 

But of course, the Fates never made anything easy and simple for demigods. The Ferris Wheel stopped as new passengers were ushered in the other carts. At this rate, it would take at least ten minutes for Nico and Will to get off. 

That left them only one option.

Shadow travel. 

Because of "Doctor's Orders", Nico hadn't shadow travelled in weeks. He hesitated and quickly glanced at the blonde boy. Judging from the concern clear as day clouding his face, Will was thinking the same thing. Taking a big breath, Nico grabbed Will's arm and slipped into the void of darkness. 

Almost instantly, the shadows and ghosts started to whisper to him. Give up. You're done for. Come with us. You're already half a ghost anyway. Nico hesitated. But he realized that he was still clutching onto Will and regained his determination. No. I am Nico Di Angelo, the ghost king who travelled through Tartarus alone and transported the Athena Parthenos halfway across the world. I'm not scared of any of you. Summoning every inch of his strength, he concentrated to get them both out of the shadows and...

...stumbled back into reality. Straight away, Nico's knees buckled and he collapsed onto the hard concrete, exhausted. Somewhere to his right, he heard a dazed Will groan and haul himself to his feet. 

Will scrambled to where Nico lay, "Nico?" Digging into his pocket, the son of Apollo brought out a tiny KitKat bar and offered it to him. Shoving the chocolate into his mouth and slowly getting up, Nico looked around for the shadow that he saw from the top of the Ferris Wheel. 

"There," Will pointed. About 70 feet in front of them, a massive black shape loomed above the gate that separated the parking lot and the amusement park. Breaking into a run, they both shoved mortals aside and passed through the gate. 

As they got closer, they saw horns atop a bull-like head resting on a heavy body with two giant wings extending from its upper back. A massive foot attached to thick legs bulging with muscle crushed cars after cars like tin cans and similar arms with sharp claws gleamed in the sunlight. Redish black slime was dripping off its body, like sweat. The wings were pure black, full of scars and still-open cuts probably made by recent fights. Fresh black blood with a slight green tint trickled down onto the pavement and sizzled.

And the smell hit them hard like a sack of bricks. 

It reeked of death. While Will started to double over and cough, Nico brought his sleeve up to his nose and stared. Just stared. In his entire demigod life of fighting various kinds of monsters, he had never seen(or smelled)something so absurdly horrible. It looked nowhere close to what he was used to. Just when I thought I had defeated every kind of monsters that exist in Greek Mythology... 

Even though he was able to withstand the smell, the distinct squelching sounds made him want to hurl his guts up. When the monster turned around and sniffed at Will and Nico, they couldn't help but audibly gasp. It had the head of a minotaur. Its body obviously didn't belong to a minotaur though.

Before Nico could shout in warning, one of the monster's claws grabbed Will's throat and snatched him easily off the ground. And began to squeeze. As the son of Apollo kicked and fought to breathe, Nico yelled, "Over here you useless piece of bull shit." 

The minotaur -not entirely a minotaur but Nico decided it was one- hissed and glared at him. He found a loose chunk of concrete and threw it as hard as he could. It flew through the air gracefully and hit its target. The minotaur's eye. 

That successfully made it drop Will. To Nico's horror, Will was dropped headfirst. He slammed down onto the concrete and didn't move. It was hard to tell but a pool of dark red started to spread under him. 

"No, no no no," Nico screamed. He started to run toward his boyfriend but something heavy caught his throat and knocked him to the ground. It was the minotaur. He tried to stab it, but it effortlessly knocked his sword aside. And then it began to choke him. 

The son of Hades punched, kicked, and struggled just as Will had, moments before. Spots danced across his eyes and the minotaur's face was blurry. His lungs burned as they begged for air. Slowly, darkness spread from the edge of his vision. Nico knew he was going to die. No one else was here. Only mortals. The Mist probably made them blind to the nearby danger and they didn't see anything out of the ordinary. 

Will, I love you, he thought. The back of his eyes burned and tears ran down his cheeks. 

The last of what he could see turned black and the ghost king started drowning in darkness. He vaguely thought he heard a deep voice shout, "Ariel," but that was just ridiculous. Why would anyone be yelling a Disney princess's name? 

Suddenly, the burning weight on his neck lifted and he greedily sucked in air. Curled up on the hard concrete, coughing and retching, Nico tried to get up but the blinding pain kept him down. 

He thought he saw a pair of blue eyes peering down at him. But Will is unconscious, why is he standing over me? was Nico's last thought before the world turned black and he passed out.


	2. Chapter 2

**Notes for the Chapter:**

> Thanks for reading! This was supposed to be a prologue but I forgot to put it in the beginning...

The beautiful moonlight illuminated a tall girl with flowing long ink-black hair carefully perched on a window sill. Her dark brown eyes shone with excitement as she eyed the view below. Taking a deep breath, she leaped gracefully through the air and landed soundlessly on a balcony below in a crouch. 

She had been taking a midnight walk outside the New York Insitute when she heard something rustle. Just as she expected, four Shax demons were lurking in a nearby bush. Quickly uncoiling her whip, she spun and brought it down in a wide arc, instantly taking them out. Satisfied, she had smiled and was heading back to the Institute when she spied another Shax demon. For hours, she had run after it all over Manhatten. At one point, it disappeared and she had to run across the rooftops scanning the area with her Sensor. 

And finally, in her hand, it started to warm and vibrate slightly. Following its pulse, she found herself led to an abandoned run-down building in a small, dark alley far away from the main commotion of the city. Cautiously, she slid into a fighting stance at the mouth of the alley and started to approach the Shax demon scurrying around the garbage cans and cardboard boxes dumped to the side. 

As if on cue, a thick mist started to envelop her surroundings and she couldn't even see two feet in front of her. It was nothing like morning fog. It was more dense and seemed to have a mind of its own as it swirled and danced around her. And she swore she saw different images whirl and flash by so fast they all blurred together. Suspicious sounds of something scurrying, and shrieks that definitely could not belong to any human echoed into her ears.

Knowing that the Shax demon, or even worse, whatever that was controlling the mist, something even more powerful than the demon, could attack her at any moment, she started to back away quietly. Holding her breath and hoping that she didn't trip over anything on the ground, or worse, go in the wrong direction, she slowly made her way back to the mouth of the alley. When she saw her own shadow on the uneven sidewalk, she allowed herself to breathe again. 

She looked up again, to her astonishment, the whole alley was gone. No run-down buildings, garbage cans, cardboard boxes, and abandoned furniture she saw earlier laid around. Only dirt, a couple of rocks, and rats scurrying around remained. Rubbing her eyes, she was tempted to walk through it to make sure what she saw, but in the end, she knew she would need back up before she could explore it again. She didn't know what was in the mist that had surrounded her, or the building. 

Looking up at the sky, she saw that it had started to lighten slightly and broke into a run. A meeting at the Institute would start when the sun rose. She couldn't arrive late. In the next twenty minutes, she would have to race back, put on non-blood-stained clothes, wipe the rest of demon blood off of her whip, and make herself look presentable. 

Cursing herself for not checking the time while demon hunting, she jumped and vaulted onto a fire escape mounted on a nearby building and raced up the steps. Running on rooves would be faster, she decided. That way, she could avoid dodging cars and early joggers. At last, she saw the top of the Insitute and poured in last-minute speed to her legs. And almost skidded to a stop. 

There was a big road was sandwiched between the roof she was on and the one she had to get onto next. In less than three seconds, she had to make a decision. Either make herself stop, or take a huge risk and try to jump the gap. Praying that her strength and agility runes she Marked earlier still worked, she pushed off the edge of the roof with her foot as hard as she could and...

... a laugh of delight escaped her lips as she flew through the early morning air nimbly. Successfully landing softly on the roof, she started sprinting for the Institute once more. 

Scrambling down a fire escape, she dove through the window into her room. Checking the clock, she realized that she made a mistake when estimating the time she had before the meeting. There was still more than half an hour left. Which meant she had time to eat too if she kept up her pace. 

Smiling in relief, she kicked off her boots, took off her fighting gear, jumped into the shower, got into fresh clothes and quickly tidied up her hair before calmly walking into the kitchen. 

"Good Morning," Isabelle Lightwood said to no one in particular, plopped down in her regular chair, and accepted some eggs from her brother.


End file.
